In the fields of molecular biology and biochemistry, biopolymers such as nucleic acids and proteins from organisms are identified and/or fractionated in order to search for useful genes or to diagnose diseases. A hybridization reaction is frequently used as a pretreatment for such process, where a target molecule in a sample is hybridized with a nucleic acid or a protein having a known sequence. For this purpose, microarrays, or so-called biochips or DNA chips, are used on which probes such as DNAs, RNAs or proteins with known sequences are immobilized at predetermined positions.
On a microarray, a plurality of regions called features are defined on which different probes are immobilized. The microarray is placed into a reaction container together with sample DNA or the like to allow the fluorescence-labeled sample DNA to hybridize with the probes immobilized on the respective features of the microarray. Thereafter, the microarray is irradiated with excitation light to measure fluorescent intensity of each feature. Based on the measured fluorescent intensities, the binding levels between the respective probes and the sample DNA are obtained and converted into desired information.
Currently, there are roughly two methods for producing microarrays. One is a method in which oligonucleotides are synthesized on a microarray support, and the other is a method in which samples such as cDNAs are spotted on a microarray support. The latter microarray production method generally uses pins for capturing samples from wells of a well plate storing the samples and immobilizing the samples onto the microarray support. In order to improve speed of producing the microarray, a plurality of pins are used simultaneously. Since many microarray experiments require to measure quantitative differences between the spots, great care should be taken to produce uniform pins and to accurately attach pins to a device not to cause any spotting amount error between the plurality of simultaneously-used pins.
However, as the number of the simultaneously-used pins are increased in order to perform faster microarray production, it becomes more difficult to equalize the spotting amounts of the pins by production of uniform pins and by accurate attachment of the pins to the device (i.e., by hardware means).
In view of the above-described problems, the present invention has objectives of providing a microarray which does not have an influence on measurement results even when there is a difference of spotting amount between pins, a method for producing such microarray, and a method for correcting an inter-pin spotting amount error of a microarray.